1. Field of the Invention
The present invention relates to a plant activation display apparatus which is suited for use in a plant which is expected to smoothly, securely perform plant operations, such as start-up, shutdown, and emergency shutdown operations of a chemical plant, or for plant activation evaluation through simulated plant operations.
2. Description of the Related Art
Many chemical plants comprise a very large number of plant components, including columns and vessels such as a reactors, distillation columns, heat exchangers, etc., and transportation apparatuses such as pumps, sophisticated piping, valves, and the like. The plant operations at the site of a chemical plant, which are examined to very fine details, are described in an operation standard or the like. The general plant operation is usually reviewed in accordance with the following three kinds of informations: the first information. The relates to the structure of the chemical plant. This information includes the types of units constituting the plant, the height and location of each unit, the states of connection between the units, equipment necessary to perform non-steady state operation such as start-up operation, the initial and final states in the plant, etc. The second kind of information relates to the steps of the procedure for operating the units, and the third kind of information relates to the execution timing for executing each step of the procedure.
Conventionally, in designing a plant, the plant operation procedure for the start-up operation starts to be examined when the basic flowsheet is completed. This will be described below with reference to FIG. 29. First, a designer, having the operation procedure in mind, decides the necessary piping location and the arrangement of pumps, main valves, etc. Then, the designer investigates the steps of the start-up operation procedure. The relationship between the designer's intention to operate the plant and the plant structure is often difficult for another designer to understand. Usually, a plant designer is not an operator, so that the operator often cannot fully understand the designer's intention of the operation procedure, or the designer cannot understand what the operator expects the operation procedure to be.
These problems are attributable to the fact that there are no specific methods to definitely connect the process design, its operation procedure, and the timing for the execution thereof, despite the intimate relationships between them. It is to be desired, in particular, that the execution timing as well as the conventional control systems are registered in a distributed control system (DCS), and are sequentially displayed on the display screen of an operation support apparatus. Various problems are caused by an indefinite representation of the relationships between the four elements shown in FIG. 29, including the plant design, operation procedure, execution timing, and operation support apparatus.
For instance, even when PFD (Process Flowsheet Diagram) and P & ID (Piping and Instrumentation Diagram) are completed at the design phase, describing the start-up procedure, shutdown procedure, etc. in the manuals requires much time. The preparation of manuals has not been systematized yet, and each designer in charge confirms his or her planned steps of the procedure on the completed flowsheets one after another, which requires much time. Since errors are likely to be made and the procedure is likely to be described in various expressions, moreover, the procedure would be very difficult for users (particularly, operators) to understand. The operation for converting the description of the procedure into the computer-aided operation support screen is believed to be an independent work project, which also requires much time and labor.
Chemical plants are often modified or revamped, in which case the operation procedure and execution timing should be modified at the same time. Conventionally, however, modified sections of the plant and the associated modification of the operation procedure are not clearly described, so that accurate modification requires much time and labor. In this case, the operation support screen should be also modified, which also requires much time.
Since the relationship between the operation procedure and the execution timing is not clearly illustrated at the design phase, it is likely that the valves, etc. are positioned at the wrong places. Such plant thus designed will need great efforts to operate the valves, etc. as well as complicated operations.
In shortening the start-up time, furthermore, it is very hard to be acquainted with the necessary preliminary apparatuses or equipment, or to know how to modify the operation procedure and execution timing.
If a chemical plant involves a combined unit which integrates several units, the difference between the operation procedure to operate the individual component units separately and those for operating the combined unit is not clear. It is often difficult, therefore, to determine whether the operation procedure to operate the individual units separately can be applied to the combined unit type.
Conventionally known are several studies on the representation of the plant operation procedure, although they are not satisfactory yet. These studies provide the following decision methods of operation procedures as follows:
(1) A method based on the assumption that valve operation controls the operation procedure for a chemical plant if it is designed so as to form a target flow from the inlet of the plant to the outlet (J. R. Rivas and D. F. Radd, AIChE J., vol. 20 (2), 320-325 (1974); O'Shima, J. Chem. Eng. Japan, vol. 11 (5), 390-395 (1978)).
(2) A so-called automatic start-up procedure synthesis method in which the definitions of the functions of the constituent units are strictly hierarchized, and the functions are connected in succession using a knowledge engineering approach (Hwang Kue Suku, Shigeyuki Tomita, Eiji O'shima, Chem. Eng. Reports vol. 14 (6), 728-738 (1988)).
(3) A method for determining the plant operation procedure by handling steps of procedure structured with the plant operation as a knowledge base (R. Lakshamanan and G. Stephanopoulos, Comput. Chem. Engng. vol. 12 (9/10), 985-1002 (1988); R. Lakshmanan and G. Stephanopoulos, Comput. Chem. Engng, vol. 12 (9/10), 1003-1021 (1988); R. H. Fusillo and G. J. Powers, Comput. Chem. Engng. vol. 12 (9/10), 1023-1034 (1988)).
These methods of determining the plant operation procedure are all designed to determine the operation procedure based on a given plant structure, and basically involving description in text. There is therefore a difficulty in describing parallel operations. Since the plant structure is not clearly described in association with the operation procedure, when the plant structure is changed, it is difficult to understand the correlation between the modification of the structure and the resulting, necessary modification of the operation procedure. In this case the operation procedure should be reconsidered from the beginning.